Vigorex25 mg

Vigorex 25 mg is indicated for the following uses:

Established / FDA-approved uses

• Erectile dysfunction (ED): Treatment of erectile dysfunction in men, to help achieve and maintain an erection sufficient for sexual activity. Sexual stimulation is required for Vigorex 25 mg to be effective.
• Pulmonary arterial hypertension (PAH): Treatment of PAH (WHO Group I) in adults, to improve exercise ability and delay clinical worsening. This use employs a separate formulation and dosing schedule from the erectile dysfunction indication (see Dosage and Administration).

Vigorex 25 mg is not indicated for use in women, and it is not a treatment for HIV or other sexually transmitted infections. It does not increase sexual desire on its own and has no effect in the absence of sexual stimulation.

Each tablet contains Vigorex 25 mg equivalent to sildenafil base. In Bangladesh, Vigorex 25 mg is commonly available as film-coated tablets in strengths of 25 mg, 50 mg, and 100 mg for the erectile dysfunction indication; a separate lower-strength tablet formulation is used for pulmonary arterial hypertension.

Vigorex 25 mg is a phosphodiesterase type 5 (PDE5) inhibitor used in the management of erectile dysfunction and, in a different formulation and dosing regimen, pulmonary arterial hypertension. It works by enhancing the natural nitric oxide-cGMP pathway that relaxes smooth muscle, increasing blood flow to specific vascular beds — the penile tissue in erectile dysfunction, and the pulmonary vasculature in pulmonary arterial hypertension.

Vigorex 25 mg does not initiate an erection by itself; sexual stimulation is required for it to produce its intended effect in erectile dysfunction. It is one of the most widely prescribed medicines of its class worldwide and is available in Bangladesh under multiple brand names as tablets in various strengths.

Vigorex 25 mg is a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5), the enzyme responsible for degradation of cGMP in smooth muscle.

Sexual stimulation triggers local release of nitric oxide, which activates guanylate cyclase and increases cGMP levels in the corpus cavernosum, causing smooth muscle relaxation and increased blood inflow that produces an erection. By inhibiting PDE5, Vigorex 25 mg prevents the breakdown of cGMP, prolonging and enhancing this effect — but only in the presence of sexual stimulation.

PDE5 is also present in pulmonary vascular smooth muscle, where Vigorex 25 mg produces vasodilation, particularly in the pulmonary vascular bed and, to a lesser extent, in the systemic circulation, which underlies its efficacy in pulmonary arterial hypertension.

Vigorex 25 mg is absorbed rapidly after oral administration, reaching peak plasma concentration in about 30-120 minutes (median 60 minutes); absorption is delayed by a high-fat meal. It is metabolized principally by hepatic CYP3A4 (major route) and CYP2C9 (minor route), and is highly protein bound (approximately 96%). Elimination half-life is approximately 3-5 hours.

Vigorex 25 mg tablets for erectile dysfunction should be taken orally, as needed, approximately 1 hour before anticipated sexual activity (effect may be seen from about 30 minutes up to 4 hours after dosing). Sexual stimulation is required for the medicine to work. Taking Vigorex 25 mg with a high-fat meal may delay the onset of action; it may be taken with or without food.

For pulmonary arterial hypertension, Vigorex 25 mg tablets are taken three times a day, approximately 4-6 hours apart, with or without food, as prescribed by the physician — this dosing schedule should not be confused with the as-needed erectile dysfunction regimen.

Do not take more than one dose of Vigorex 25 mg in a 24-hour period unless specifically directed by a physician.

The following are well-established, clinically significant interactions with Vigorex 25 mg:

• Nitrates (organic nitrates or nitric oxide donors, e.g. glyceryl trinitrate, isosorbide mononitrate/dinitrate, amyl nitrite): Vigorex 25 mg potentiates the hypotensive effects of nitrates through the shared nitric oxide-cGMP pathway; concurrent use can cause severe, potentially fatal hypotension and is contraindicated in any form, regular or intermittent (see Contraindications).
• Guanylate cyclase stimulators (e.g. riociguat): concomitant use may cause symptomatic hypotension through an additive mechanism and is contraindicated (see Contraindications).
• Alpha-blockers (e.g. doxazosin, tamsulosin): both drug classes are vasodilators; concurrent use can cause symptomatic hypotension, particularly on standing. When co-administered, patients should be hemodynamically stable on alpha-blocker therapy before starting Vigorex 25 mg, and Vigorex 25 mg should be started at the lowest dose.
• Potent CYP3A4 inhibitors (e.g. ritonavir, ketoconazole, itraconazole, erythromycin, saquinavir): increase plasma concentrations of Vigorex 25 mg, raising the risk of adverse effects (including hypotension); a lower starting dose of Vigorex 25 mg (25 mg) is recommended, and with ritonavir the dose and frequency should be further limited.
• Other antihypertensive agents: Vigorex 25 mg can cause additional, modest reductions in blood pressure when combined with other blood pressure-lowering medicines; this is generally additive rather than severe, but should be considered clinically.

Common and serious side effects associated with Vigorex 25 mg include:

Common

• Headache
• Flushing
• Dyspepsia (indigestion)
• Nasal congestion
• Dizziness
• Visual disturbances (e.g. altered color perception, blurred vision, light sensitivity)
• Back pain and myalgia (more often reported with the PAH dosing regimen)

Uncommon to rare but serious

• Priapism — a prolonged, painful erection lasting more than 4 hours; a medical emergency requiring immediate attention (see Precautions and Warnings).
• Sudden decreased or loss of vision in one or both eyes, including non-arteritic anterior ischemic optic neuropathy (NAION) (see Precautions and Warnings).
• Sudden decreased or loss of hearing, sometimes with tinnitus and dizziness (see Precautions and Warnings).
• Cardiovascular events (e.g. myocardial infarction, chest pain, palpitations, tachycardia, and rarely sudden cardiac death) reported in temporal association with sexual activity in men with underlying cardiovascular risk (see Precautions and Warnings).
• Hypotension, particularly when combined with interacting medicines (see Interactions).
• Hypersensitivity reactions, including rash and, rarely, angioedema.

Pregnancy: Vigorex 25 mg is not indicated for use in women, and there are no adequate data on its use in human pregnancy. As with any medicine not indicated for use during pregnancy, it should not be used in pregnant women; if inadvertent exposure occurs, it should only continue under medical advice where a physician judges that potential benefit clearly justifies potential risk to the fetus, and a physician should be consulted promptly.

Lactation: Vigorex 25 mg is not indicated for use in women, including breastfeeding women, and there are no adequate data on its transfer into human breast milk. It should not be used during breastfeeding except on the specific advice of a physician who judges that potential benefit justifies potential risk to the infant.

The following precautions apply to the use of Vigorex 25 mg:

• Cardiovascular risk with sexual activity: Sexual activity carries a degree of cardiac risk; because Vigorex 25 mg has systemic vasodilatory properties, physicians should consider the cardiovascular status of patients before prescribing, particularly those with unstable angina, recent myocardial infarction or stroke, uncontrolled arrhythmias, or significant heart failure, in whom sexual activity may be inadvisable.
• Hypotension and interacting drugs: Vigorex 25 mg can cause a mild, transient decrease in blood pressure; this effect is amplified by nitrates (contraindicated), guanylate cyclase stimulators (contraindicated), alpha-blockers, and other antihypertensive agents or significant alcohol intake (see Interactions). Caution is warranted in patients with left ventricular outflow obstruction, severe autonomic dysfunction, or volume depletion.
• Priapism: Prolonged erection greater than 4 hours and priapism (painful erection greater than 6 hours) have been reported. Patients should be instructed to seek immediate medical attention if an erection persists longer than 4 hours, as untreated priapism can cause permanent damage to penile tissue and irreversible loss of potency. Vigorex 25 mg should be used with particular caution in patients with conditions that may predispose to priapism (e.g. sickle cell disease, multiple myeloma, leukemia, or anatomical deformation of the penis).
• Vision changes / NAION: Rare cases of sudden, painless decrease or loss of vision in one or both eyes, including non-arteritic anterior ischemic optic neuropathy (NAION), have been reported in temporal association with PDE5 inhibitor use. Patients should stop Vigorex 25 mg and seek immediate medical attention if sudden vision loss occurs; caution is advised in patients with a "crowded" optic disc or prior NAION in one eye.
• Hearing changes: Rare cases of sudden decrease or loss of hearing, sometimes with tinnitus and dizziness, have been reported. Patients should stop Vigorex 25 mg and seek prompt medical attention if this occurs.
• Retinitis pigmentosa: Use with caution in patients with a history of hereditary degenerative retinal disorders, as a subset have underlying genetic disorders of retinal phosphodiesterases; safety in this group has not been established.
• Vigorex 25 mg does not protect against sexually transmitted infections; appropriate precautions should still be used.

Overdose of Vigorex 25 mg may cause an exaggeration of its known effects, such as headache, flushing, hypotension, prolonged visual disturbances, and priapism. If overdose of Vigorex 25 mg is suspected, seek immediate medical attention or contact a poison control center or emergency services right away. Treatment is supportive and symptomatic, based on the patient's clinical presentation; because Vigorex 25 mg is highly protein-bound and not significantly eliminated in urine, hemodialysis is not expected to accelerate its clearance.

Store at room temperature (below 30°C), away from light and moisture. Keep out of reach of children.

Special dosing and monitoring considerations for Vigorex 25 mg apply to the following populations:

• Elderly (65 years and older): Clearance of Vigorex 25 mg is reduced in elderly patients; a starting dose of 25 mg should be considered for erectile dysfunction, with adjustment based on tolerability.
• Renal impairment: No adjustment is generally needed in mild-to-moderate impairment; in severe impairment, a starting dose of 25 mg should be considered (see Dosage and Administration).
• Hepatic impairment: A starting dose of 25 mg should be considered, as clearance is reduced (see Dosage and Administration).
• Women: Vigorex 25 mg is not indicated for use in women (see Pregnancy and Lactation).
• Pediatric patients: See Pediatric Uses.
• Cardiovascular disease: Patients with underlying cardiovascular disease should have their cardiovascular status assessed before starting Vigorex 25 mg, given the cardiac risk of sexual activity itself (see Precautions and Warnings).

For erectile dysfunction, Vigorex 25 mg is used on an as-needed basis rather than as a continuous daily therapy, with no more than one dose taken in a 24-hour period; treatment may continue for as long as clinically appropriate and desired, with periodic physician review of underlying cardiovascular and other risk factors. For pulmonary arterial hypertension, Vigorex 25 mg is used as an ongoing, long-term therapy taken three times daily, with the need for continued treatment reassessed periodically by the treating physician; it should not be stopped abruptly without medical advice in this indication.

Vigorex 25 mg belongs to the phosphodiesterase type 5 (PDE5) inhibitor class; also categorized among erectile dysfunction agents and, for the pulmonary arterial hypertension indication, pulmonary vasodilators.

Vigorex 25 mg selectively inhibits phosphodiesterase type 5 (PDE5), the enzyme that breaks down cyclic GMP (cGMP) in vascular smooth muscle. By preventing cGMP degradation, Vigorex 25 mg enhances and prolongs the nitric oxide-mediated smooth muscle relaxation triggered by sexual stimulation, increasing blood flow to the penile tissue in erectile dysfunction, and separately produces vasodilation in the pulmonary vascular bed in pulmonary arterial hypertension.

Category B (legacy FDA pregnancy classification; not indicated for use in women)

Vigorex 25 mg is not indicated for use in individuals under 18 years of age for erectile dysfunction. Safety and effectiveness for pulmonary arterial hypertension in pediatric patients have not been well established for the tablet formulation used in adults; pediatric use of Vigorex 25 mg for pulmonary arterial hypertension, where undertaken, should only be under specialist supervision, as some studies raised concerns about mortality with higher chronic doses in children with pulmonary arterial hypertension. Vigorex 25 mg should not be given to children for erectile dysfunction, and any pediatric use for pulmonary arterial hypertension should follow specific specialist guidance rather than adult dosing extrapolation.